25-4. Jumpers meet the following requirements: All jumpers are not less than Class 3 basic water survival swimmer qualified in accordance with TC 21-21 (U.S. Marine Corps combat water survival-1 or higher, U.S. Navy second class swimmer, qualified SEAL, SWCC, EOD, or U.S. Navy diver). All jumpers have completed drown-proofing training within the preceding 12 months. All jumpers have been trained on activation procedures for the life preserver in use, to include manual inflation procedures. All jumpers have attended prejump training on deliberate WDZ procedures according to the unit SOP. All combat equipment is float-checked. Jumpers jumping in cold water (60 degrees or lower) will wear wetsuits or dry suits. Drop control is visual marking system. Helicopter is flying under visual flight conditions. Briefing held for WDZ operations by DZSO or DZSTL, and WDZ control personnel.WARNINGAll jumpers conducting a deliberate water landing must be prepared to conduct a PLF in the event the jumper fails to land inside the surveyed DZ or during emergency bailout procedures.